HPV: the potentially cancerous STD

by Heather Smith

Human papillomavirus (HPV), the virus strongly linked to cervical cancer, is one of the most common sexually transmitted diseases (STDs). What makes it different from other STDs is its widespread prevalence.

Two years ago, 22-year-old Cindy went in for her yearly pap smear. She endured the usual indignity of the vaginal and cervical exam, and went home thinking nothing of it. When her gynecologist told her that her pap smear had come back abnormal with possible mild dysplasia and HPV-associated changes, she was surprised, to say the least. Cindy had never heard of HPV, which is the virus that causes genital warts. Even more disconcerting was the fact that both her parents had died of cancer within the last three years. Because HPV is linked to cervical cancer, she was afraid that this condition would progress into cancer, too.

One million new people each year get HPV-related genital warts. This is in addition to the estimated 24 million who already suffer from them, according to the National Institute of Allergy and Infectious Diseases. Researchers estimate that, like Cindy, even more people contract HPV and never get the warts. One international study found HPV DNA in 93% of women with cervical cancer. Despite these statistics, a recent survey revealed that only one in every four women had ever heard of HPV.

Human papillomavirus binds to the skin cells, and can "sleep" for months or even years. Genital warts and sometimes even warts on the hands and face spring from HPV. Warts may appear on the vagina, cervix, penis, urethra or anus. They are usually flesh-colored bumps, appearing alone or in cauliflower-like clusters. Most are painless, though some are painful, itchy, or both.

But most HPV types cause invisible warts or no warts at all. These "subclinical" infections surface as dysplasia (abnormal cells) on a pap smear. Because men are not routinely tested in the genital area, they usually don't get these advance hints of the virus. But according to Dr. Edward Partridge, National Cancer Institute (NCI) investigator and University of Alabama's director of gynecology and oncology, "almost certainly if the woman has papillomavirus and has been sexually active, her male partner will have the virus also." Although the virus has been discovered in most cases of cervical cancer, it's only been found in some cases of penile cancer, which is a very rare cancer.

Unlike most sexually transmitted diseases, HPV travels via skin and not via blood or body fluids. Therefore, transmission risk is high. Indeed, one study at the University of Washington revealed that 80% of people with no more than four sex partners had HPV. Even a condom isn't entirely protective, because it leaves bare the vulva, anus, scrotum, and penis. It's also possible for pregnant women to pass HPV to their babies. Long-term studies are underway to clarify this risk.

With HPV, like many other STDs, being symptom-free doesn't mean that it's entirely safe to have sex. Margaret Bridwell, MD, a member of American Social Health Association's (ASHA) HPV Advisory Board, warns, "People have got to understand that even though they don't see any warts they can still be contagious."

HPV is not synonymous with cancer. Though certain subclinical types of HPV turn up in most cervical cancers, the wart-forming types almost never cause cancer. Both high- and low-risk types of the virus can cause abnormal pap smears. But Dr. Partridge says, "Although about 10%-15% (of abnormal paps) will show high grade dysplasia on biopsy, cancer will be a very rare event." Most doctors recommend that women who have had one abnormal pap smear repeat them every six months for at least three years.

In addition to HPV, behaviors like smoking, multiple sex partners, and having sex at a young age also possibly heighten the risk of cervical cancer.

Genital warts are clear evidence of HPV; otherwise, most people never know for certain that they have the virus. Only DNA testing can definitively prove the presence of HPV in women. No FDA-approved DNA test exists for men.

A diagnosis of HPV is made after an abnormal pap smear by looking at the cervix through a microscope-like device. Signs of the virus like tiny warts or dysplasia are noted. A biopsy is often done as well.

Some practitioners choose not to do this right away. Instead they wait six months and do a second pap. Thomas Sedlacek, MD, another ASHA HPV Advisory Board member, says that a woman's second pap is normal "in the vast majority of cases." However Dr. Bridwell cautions, "It's never safe to say the virus is gone." Researchers estimate that 90% of all abnormal paps are infected with human papillomavirus DNA.

Like herpes and AIDS, no cure exists for HPV, though scientists are researching a vaccine that has worked on animals.

Between 10% and 30% of warts regress spontaneously, but physicians cannot predict those that will regress. Topical ointments are also available for treatment. Podofilox (Condylox) uses an active ingredient found in another anti-wart medication, podophyllin (Podofin, Pod-Ben 25), which is made from the resin of the mandrake tree.

A topical treatment applied three times a week Imiquimod 5% has shown promise in treating genital warts. In two clinical trials, at least 50% of patients receiving this treatment had a complete clearance of their warts. After the trials were over and patients entered a 12-week Imiquimod-free period, the recurrence rates were low. According to one of the researchers associated with the trials, the benefit of imiquimod lies with the fact that it is well tolerated in comparison with other medications and therapies. Trichloroacetic acid is another skin treatment being tried, but it is very caustic and some studies have found it ineffective.

If other treatments fail and the patient is otherwise healthy, interferon-alpha (Alferon N, Intron A) can be used. The drug is injected into genital warts two or three times weekly for about eight weeks. It is very expensive and has a high incidence of unpleasant side effects. An injectable gel (Accusite) containing the anti-cancer drug fluorouracil (5-FU) is proving to be safe and effective for genital warts. Other experimental drugs include afovirsen, which blocks HPV from using its own genes, and GS504, which may block the virus from replicating.

If necessary, HPV warts can also be treated using cryosurgery with liquid nitrogen or surgically using conventional procedures or carbon dioxide laser. Until scientists perfect ways to specifically target and kill the virus, no treatment is foolproof. Although warts can be removed, microscopic HPV infection will still be present. Although warts may disappear on their own, many researchers support wart removal, because it reduces transmission risk, and helps people feel better about their condition. Dr. Partridge asserts that a woman should always have a biopsy to determine the extent of her dysplasia before having any surgery done.

Every man and woman who is sexually active is at risk for HPV. Condoms are definitely required because they shield the most contagious body parts, but even they aren't foolproof.

Cindy only had five sexual partners, three with whom she used condoms. For a year her pap came back normal, but her last one came back abnormal. Dr. Partridge remarks, "If you have a monogamous relationship with someone who doesn't have the virus, you're not going to get the virus." In the absence of a practical screening test, indiscriminate sex can be a gamble.